 (def power-as (as-f :hp :W 745.69987158227022))
 (def pressure-as (as-f :psi :kPa 6.894757293168361))
 (def proppant-concentration-as (as-f :lb-per-gal :kg-per-m3 119.826))
-(def slurry-rate-as (as-f :bpm :m3-per-min 6.28981077))
+(def slurry-rate-as (as-f :m3-per-min :bpm 6.28981077))
 
 ;; Because conversion between temperature units is not simply multiplicative, I define this function with a
 ;; unique body.

        measurement (generate-measurement-f unit)]
    [measurement (measurement-as-f measurement (first (remove (partial = unit) units)))]))

(generate-measurement-pair #{:lb-per-cu-ft :kg-per-m3} rand-density-unit typical-density density-as)

(defn rand-physical-quantity []
  (rand-nth physical-quantities))

(def quantity-unit-map {:density                [:lb-per-cu-ft :kg-per-m3]
                        :energy                 [:ft-lb :J]
                        :force                  [:lbf :N]
                        :length                 [:ft :m]
                        :mass                   [:lb :kg]
                        :power                  [:hp :W]
                        :pressure               [:psi :kPa]
                        :proppant-concentration [:lb-per-gal :kg-per-m3]
                        :temperature            [:F :C]
                        :slurry-rate            [:bpm :m3-per-min]
                        :volume                 [:bbl :m3]})


(defn rand-unit [physical-quantity]
  (rand-nth (get quantity-unit-map physical-quantity)))

(repeatedly 25 (fn [] (let [physical-quantity (rand-physical-quantity)]
                        [physical-quantity (rand-unit physical-quantity)])))


(def rand-density-unit (rand-unit :density))
(def rand-energy-unit (rand-unit :energy))
